Automatic electric fire-alarm.



PATENTED JAN. 15,1907.

W. G. MEDDINGS. AUTOMATIC ELECTRIC FIRE ALARM.

APPLICATION FILED MAR. 6, 1906.

waxed 5,

WILLIAM GEORGE MEDDINGS, OF REMUERA, NEAR AUCKLAND, NEW

ZEALAND.

AUTOMATIC ELECTRIC FIRE-ALARM.

Specification of Letters Patent.

Patented Jan. 15, 1907.

Application filed March 6, 1906. Serial No. 304,569,

To all whom it may concern.-

Be it known that LWVILLIAM GEORGE MED- DINGS, inspector of New Zealandtelegraphs,

a subject of His Majesty the King of the 1 United Kingdom of GreatBritain and Ireland, and a resident of Remuera, near the city ofAuckland, in the Provincial District of Auckland and Colony of NewZealand, have invented an Automatic Electric Fire-Alarm, of which thefollowing is a specification.

The purpose of this electric fire-alarm is to give the alarm whereverthe apparatus is fixed on the temperature of the room, chamber, orcompartment rising to 150 Fahrenheit and upward. This is accomplished bya disk or piece of metal held by claws softening by the increase ofheat, so releasing the tension of the rod pressing thereon, and therebypermitting the spring pressed up by the rod to engage the fixedconnection whereby contact is made, an electric circuit established, andthe alarm given by means of any suitable apparatus fitted thereto.

The accompanying drawings, which are full size, show three figures, ofwhich Figure 1 is an elevation of the electric alarm device, showingportion of its upper part broken. Fig. 2 is a sectional view of thedevice, and Fig. 3 is a perspective view of the disk or piece of metalfitted to the claw-legs.

The disk 01' piece of metal A is made of a composition, preferably of amixture of bis muth, tin, and lead, which softens in an atmosphere of atemperature of 150 Fahrenheit and upward and is held in a claw formationB, made by three pieces of brass wire C, which are screwed or otherwisefixed or attached to oneend D of a small brass tube E. A small brass rodF is passed up the center of the tube E, the lower end G of which isplaced and pressed against the middle of the disk or plate A. The rod Fis held in position by a spiral spring H, one end of which pressesagainst the bottom of the case K, the other end against the nut X, whichis fixed to the rod F, thus causing a continuous pressure on the centerof the piece of metal A. The upper end J of the rod F passes upwardlyout of the tube E into a small case K, attached to the tube E. Twoelectric contacts M and N, made of thin metal, are adjusted inside thecase K, as shown in Fig. 2, M being a movable spring, and N a fixture.The end J of the rod F raises the spring M up and keeps a space betweenit and the metal N, while the disk or piece A retains its normalcondition. Then, however, the temperature is raised to 150 Fahrenheit orover, the

pressure exerted 011 the spiral spring H on the rod overcomes theresistance of the disk or piece A, which has softened by the increasedheat, so that it bulges and breaks and allows the spring M to formcontact with the fixed piece N, thereby establishing an electric circuitand giving an alarm by means of the apparatus and batteries connected tothe wires P and R. V ulcanite S or any insulating material is fitted incap 0 and in the top part of the upper case T to prevent the wire beingin any way brought into accidental contact with the case. Bayonet-jointsU are provided in the upper and lower cases to provide for their beingheld together, as required, and screws to hold the vulcanite andinsulated wires in position. The nut TV is fastened to the under part ofthe lower case K and is inwardly screw-threaded, so that the top of thetube E, which is outwardly screw-threaded, can be screwed into it and sobe attached to the case K or may be bayonet-jointed, as desired.

The outer parts of the apparatus, except the disk or piece of metal A,are coated with aluminium paint, so as to protect it from foul air,moisture, and other corroding agencies. This apparatus may be fitted inbuildings and ships of all descriptions and any number of contacts(apparatus described above) fitted in parallel right throughout ordivided into sections, as may be desired. The number of contacts fixedin each room, chamber, compartment, or hold of vessel would be inproportion to the area of same.

Having fully described my invention, what I desire to claim and secureby Letters Patent is 1. The combination in the automatic electricfire-alarm specified of the disk or piece of metal made of a mixture ofbismuth tin and lead which will soften in a temperature of 150Fahrenheit held in claw formation of three pieces of brass wire fixed'toone end of small brass tube, small brass rod passed up center of saidtube with lower end of said rod placed to press against middle of saiddisk or piece of metal, spiral spring around said rod held between nutfixed to said rod and lower case, upper end of said rod passing upwardlyout of said tube into said lower case, electric contacts adjusted insideof said case one being a fixture and the other movable, upper end ofsaid rod fitted to actuate said movable contact, insulated wiresconnected to said contacts upper case and bayonet-joints fitted thereinand in lower case, cap on top of upper case, vulcanite fitted in saidcap and top of upper case, nut fastened to under part of said lower caseand upper end of said tube-screw fitted to said nut for the purpose setforth substantially as described and illustrated.

2. The combination in the automatic electric fire-alarm specified of thedisk or piece of metal made of a mixture of bismuth tin and lead whichwill soften in a temperature of 150 Fahrenheit held in claw formation ofthree pieces of brass wire fixed to one end of I small brass tube, smallbrass rod passed up center of said tube with lower end of said rodplaced to press against middle of said disk or piece of metal, spiralspring around said rod held between nut fixed to said rod and lowercase, upper end of said rod passing upwardly out of said tube into saidlower case, electric contacts adjusted inside of said case one being afixture and the other movable, upper end of said rod fitted to actuatesaid movable contact, insulated wires connected to said contacts and tosource of electrical energy an upper and lower case provided withbayonetjoints, cap on top of upper case, vulcanite fitted in said capand top of upper case, nut fastened to under part of said lower case andupper end of said tube-screw fitted to said nut for the purpose setforth substantially as described and illustrated.

' WILLIAM GEORGE MEDDINGS. Witnesses:

GEORGE WILLIAM BASLEY, HILDA MAY FRoUDE.

